freemarker.template.utility.DeepUnwrap Maven / Gradle / Ivy
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Google App Engine compliant variation of FreeMarker.
FreeMarker is a "template engine"; a generic tool to generate text output based on templates.
/*
* Copyright (c) 2003 The Visigoth Software Society. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Visigoth Software Society (http://www.visigoths.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
* project contributors may be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
* nor may "FreeMarker" or "Visigoth" appear in their names
* without prior written permission of the Visigoth Software Society.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Visigoth Software Society. For more
* information on the Visigoth Software Society, please see
* http://www.visigoths.org/
*/
package freemarker.template.utility;
import java.util.ArrayList;
import java.util.HashMap;
import freemarker.core.Environment;
import freemarker.ext.util.WrapperTemplateModel;
import freemarker.template.AdapterTemplateModel;
import freemarker.template.ObjectWrapper;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateCollectionModel;
import freemarker.template.TemplateDateModel;
import freemarker.template.TemplateHashModelEx;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateModelIterator;
import freemarker.template.TemplateNumberModel;
import freemarker.template.TemplateScalarModel;
import freemarker.template.TemplateSequenceModel;
/**
* Utility methods for unwrapping {@link TemplateModel}-s.
* @author Attila Szegedi
* @version $Id: DeepUnwrap.java,v 1.6 2005/06/16 18:13:58 ddekany Exp $
*/
public class DeepUnwrap
{
private static final Class OBJECT_CLASS = Object.class;
/**
* Unwraps {@link TemplateModel}-s recursively.
* The converting of the {@link TemplateModel} object happens with the following rules:
*
* - If the object implements {@link AdapterTemplateModel}, then the result
* of {@link AdapterTemplateModel#getAdaptedObject(Class)} for Object.class is returned.
*
- If the object implements {@link WrapperTemplateModel}, then the result
* of {@link WrapperTemplateModel#getWrappedObject()} is returned.
*
- If the object is identical to the null model of the current object
* wrapper, null is returned.
*
- If the object implements {@link TemplateScalarModel}, then the result
* of {@link TemplateScalarModel#getAsString()} is returned.
*
- If the object implements {@link TemplateNumberModel}, then the result
* of {@link TemplateNumberModel#getAsNumber()} is returned.
*
- If the object implements {@link TemplateDateModel}, then the result
* of {@link TemplateDateModel#getAsDate()} is returned.
*
- If the object implements {@link TemplateBooleanModel}, then the result
* of {@link TemplateBooleanModel#getAsBoolean()} is returned.
*
- If the object implements {@link TemplateSequenceModel} or
* {@link TemplateCollectionModel}, then a
java.util.ArrayList is
* constructed from the subvariables, and each subvariable is unwrapped with
* the rules described here (recursive unwrapping).
* - If the object implements {@link TemplateHashModelEx}, then a
*
java.util.HashMap is constructed from the subvariables, and each
* subvariable is unwrapped with the rules described here (recursive unwrapping).
* - Throw a
TemplateModelException, because it doesn't know how to
* unwrap the object.
*
*/
public static Object unwrap(TemplateModel model) throws TemplateModelException {
return unwrap(model, false);
}
/**
* Same as {@link #unwrap(TemplateModel)}, but it doesn't throw exception
* if it doesn't know how to unwrap the model, but rather returns it as-is.
* @since 2.3.14
*/
public static Object permissiveUnwrap(TemplateModel model) throws TemplateModelException {
return unwrap(model, true);
}
/**
* @deprecated the name of this method is mistyped. Use
* {@link #permissiveUnwrap(TemplateModel)} instead.
*/
public static Object premissiveUnwrap(TemplateModel model) throws TemplateModelException {
return unwrap(model, true);
}
private static Object unwrap(TemplateModel model, boolean permissive) throws TemplateModelException {
Environment env = Environment.getCurrentEnvironment();
TemplateModel nullModel = null;
if(env != null) {
ObjectWrapper wrapper = env.getObjectWrapper();
if(wrapper != null) {
nullModel = wrapper.wrap(null);
}
}
return unwrap(model, nullModel, permissive);
}
private static Object unwrap(TemplateModel model, TemplateModel nullModel, boolean permissive) throws TemplateModelException {
if(model instanceof AdapterTemplateModel) {
return ((AdapterTemplateModel)model).getAdaptedObject(OBJECT_CLASS);
}
if (model instanceof WrapperTemplateModel) {
return ((WrapperTemplateModel)model).getWrappedObject();
}
if(model == nullModel) {
return null;
}
if(model instanceof TemplateScalarModel) {
return ((TemplateScalarModel)model).getAsString();
}
if(model instanceof TemplateNumberModel) {
return ((TemplateNumberModel)model).getAsNumber();
}
if(model instanceof TemplateDateModel) {
return ((TemplateDateModel)model).getAsDate();
}
if(model instanceof TemplateBooleanModel) {
return ((TemplateBooleanModel)model).getAsBoolean() ? Boolean.TRUE : Boolean.FALSE;
}
if(model instanceof TemplateSequenceModel) {
TemplateSequenceModel seq = (TemplateSequenceModel)model;
ArrayList list = new ArrayList(seq.size());
for(int i = 0; i < seq.size(); ++i) {
list.add(unwrap(seq.get(i), nullModel, permissive));
}
return list;
}
if(model instanceof TemplateCollectionModel) {
TemplateCollectionModel coll = (TemplateCollectionModel)model;
ArrayList list = new ArrayList();
TemplateModelIterator it = coll.iterator();
while(it.hasNext()) {
list.add(unwrap(it.next(), nullModel, permissive));
}
return list;
}
if(model instanceof TemplateHashModelEx) {
TemplateHashModelEx hash = (TemplateHashModelEx)model;
HashMap map = new HashMap();
TemplateModelIterator keys = hash.keys().iterator();
while(keys.hasNext()) {
String key = (String)unwrap(keys.next(), nullModel, permissive);
map.put(key, unwrap(hash.get(key), nullModel, permissive));
}
return map;
}
if (permissive) {
return model;
}
throw new TemplateModelException("Cannot deep-unwrap model of type " + model.getClass().getName());
}
}